The aim of the proposed work is to investigate some pathogenetic mechanisms inducing nephritis in experimental animals and in man and to study the lesions developing in human renal allografts. Renal specimens obtained from patients with glomerulonephritis or renal grafts, as well as renal tissues obtained at autopsy or after graft removal, will be studied by serological and immunopathological techniques. Comparable models of immunologically-mediated nephritides will be studied in animals. These investigations will be extended to extra-renal organs with the aim of showing that the same pathogenetic mechanism inducing renal lesions can also produce a similar injury in other highly vascularized structures. A special effort will be dedicated to the development of an experimental systemic immune complex disease comparable to systemic lupus erythematosus; to the study of its pathogenetic mechanism; and to the study of increased vascular permeability which accompany immune complex deposition in extra-renal vascular districts. A comparable effort will be dedicated to investigate the development of testicular and extra-testicular lesions in vasectomized animals and man. BIBLIOGRAPHIC REFERENCES: Milgrom, F., Campbell, W.A. and Andres, G.A. Antigen in immune complex nephritis. Recovery and identification by gel precipitation. Immunology, 30:277, 1975. Bigazzi, P.L., Kosuda, L., Hsu, K.C. and Andres, G.A. Immune complex orchitis in vasectomized rabbits. J. Exp. Med. 143:382, 1976.